This invention pertains to electrical connectors, and in particular, to an extruded metallic electrical connector assembly which has a unique module configuration having a plurality of contacts in densities of two mm or less and providing complete insulation coverage for the contacts. A method of producing an extruded metallic electrical connector assembly is also disclosed.
Electrical connectors are used in many different types of electrical and electronic systems. They come in various sizes depending on the physical and electrical parameter of the installation. Some high-speed digital signal applications require multiple contact connectors in a single rectangular module that are held together and stackable without distorting or adversely modifying the signal intelligence. Digital signals must have a high degree of signal integrity on entering and exiting an electrical connector system. Requirements for connector types, in increasingly high speed applications include a high degree of shielding, preventing signal distortion from outside Electromagnetic Interference (EMI) and low inductance and resistance for signal and return signal paths.
Rectangular connectors with multiple contacts that are 2 (two) mm or less in center spacing have limits in contact density and signal shielding by currently employed manufacturing processes. However, electronic systems that use high-speed connectors continue to shrink in physical size and require increasing signal density reducing physical size requirements for connectors. Current rectangular connectors having a plurality of contacts have limits in providing dense signal packaging and shielding of each individual contact within the connector-housing module.
Although classical round coaxial connectors have contiguous shielding along the contact length and provide low inductance and good signal integrity, they do not offer the plurality of contacts in the densities of two mm or less in a rectangular configuration. In round coaxial connections multiple contiguous contacts cannot be densely packed or stacked in a module form to densities attainable in a rectangular configuration. Connectors of a rectangular shape, having a plurality of contacts 2 mm or less for high-speed signal application, use a combination of injection molded plastics either riveted or press fitted to metal plates to simulate shielding and reduce inductance and resistance to improve signal integrity. However, these connector systems, while providing greater contact densities than round coaxial connectors, do not provide a contiguous metal cavity along the length of each individual contact. Instead only one or two sides of each individual contact has a shield vs. all 4 sides of the extruded connector-housing module described here.
U.S. Pat. Nos. 5,176,538 and 4,846,727 try to achieve a metal housing enclosure for connectors having a plurality of contacts by combining injection molded plastic pieces with metal plates added on the assembly to provide a simulated shielding configuration for the signal pin. Neither of these patents encloses each contact pin along four sides of the contact pin length and thus compromise the shielding of the individual contact pins. These connectors are limited by using traditional construction methods in signal pin density for rectangular connector modules having a plurality of contacts with contact spacing of 2 mm or less. Limits in material thickness and process controls used in assembling the connector module (injection molding, metal- stamping, press fitting etc.) limit four sided shielded density. Each contact in these multiple contact connectors is surrounded by injection molded plastic and the entire assembly or module is then fitted with metal plates on one or two sides of the assembly to provide shielding only on one or two sides of the connector-housing module.
Other contemporary U.S. Pat. Nos. 4,451,107 and 4,655,518 are also limited in creating a low inductance and low resistance path to ground. U.S. Pat. No. 4,451,107 is a die cast zinc housing to provide grounds and shields for the signals. However zinc die cast material has higher electrical resistance and inductance path then other materials like copper or copper alloy and has limits in material thickness for contact spacings on 2 mm or less.
U.S. Pat. No. 4,655,518 employs ground contacts located on the outside of the parallel casing. Neither of these patents form the low inductance and resistance path to ground afforded by a contiguous metal module that shields individual contact on all four sides in the housing module. What is needed is a multiple cavity extruded metallic electrical connector assembly that provides complete shielding for each cavity housing an electrical contact that is simple to manufacture. It is the object of this invention to teach an extruded metallic electrical connector assembly that avoids the disadvantages and limitations, recited above in other electrical connector assemblies for contact spacing on 2 mm or less.